My first impression was that the bright heart (made of frozen CO and not CO2...) looked like a "banquise" or an ice pack.

The black patches along some limits of the polygons seem to be in line with my initial assumption according to which there is a layer of liquid hydrocarbons (methane, ethane...) beneath this bright uniform crust.

At what depth?...

Possibly the largest reservoir of liquid hydrocarbons is hiding beneath this intriguing area! Who knows?

Lots of good suggestions for what is happening at Tombaugh. Gladstoner you have marked ground zero for the beginning of Charon's grazing impact. In the You Tube video stop it at 34 seconds. The depression and shock wave effects have piled up the mountains to the side of a deep circular depression, its rim wall peppered with sublimation features that look like golf bunkers. The mountain that looks like a Cathedral in this view is gigantic. We have seen before how moving images make perspective and detail easier to see and I suspect Alan has seen that and added it to improve the image presentation.

So some thoughts following a lengthy perusal of this avalanche of information.

This shot is of the very tip of the Ice Cream cone part of Tombaugh. That ice cream cone is made up of frozen Carbon Monoxide. Imagine some giant bucket of fluid Carbon Monoxide was poured on top of the existing surface of Pluto, which is a frozen Nitrogen/Methane ice layer on top of a Water Ice layer beneath. Eventually, all fluid flow stops and it freezes. The deepest point of Charon's impact is marked by the crown of the Carbon Monoxide contour map. Towards the top of the Sputnik Plain image, there is a large slightly brighter, circular area which appears to be higher and hence colder than the more Southern areas of the Carbon Monoxide Ice sea/cap, which reflects that map nicely. It is noticeable the cracks are shallower and devoid of the hills/mounds and with very few areas of dark material. At its crown is a lonely dark spot. Sublimation pit, sinkhole, geyser? No Idea.

Beneath this area's now highly impact and shock compressed surface, it may have triggered a phase change in the "bedrock" Water ice below. This releases heat and starts to warm the N2/CH4 ice mixture from below, adding to the heat from the initial impact, superheated atmosphere and shock wave, from above. Whether its enough to liquify the mixture is an open question, but convection and sublimation will occur within such "warm", porous ices. If considerable amounts of gas are trapped below the CO ice sheet the expansion of gas could create enough pressure to create the polygonal pattern.

Where cracks appear in the ice, probably forced open by the pressure from below, the Methane and Nitrogen gas are released at the surface where they are exposed to a very low pressure, gaseous Carbon Monoxide, together with UV and Cosmic Radiation. Throw in a bit of micron sized interplanetary dust, result, lots of organics, hydrocarbons, Tholins, and PAHs, which are cooked to a dark brown sludge. It may only be millimetres or centimetres thick, but the albedo contrast is stark making its distinction from shadow, difficult.

The escaping Methane and Nitrogen gas will soon freeze as an upside down icicle. Of course from long cracks, or confluences of cracks, hills, ridges and mounds would form, like growing crystals in a saturated fluid. The fact their height seems to be limited indicates they are probably not made of Water ice. Where the ice sheet is thinner, at the margins and towards the South, it is easier for the cracks to form and expand. We see many places where bits of the original underlying terrain show through, either completely or as surface topology. The nature of the original terrain can be seen in the "Ropey Mountains" far to the South, where wind, sublimation, frost deposition and thermal stress have created swirling patterns of valleys and ridges, on top of larger structures of swirling mountain chains separated by immense crevasses and canyons. Sublimation landscapes appear to show this repeating pattern on multiple scales, from micron to kilometres, as seen here and at 67P.

Lets consider Charon, possibly formed as a moon of Uranus, where, in this part of the Solar System, the predominant ices are Water and Carbon Monoxide. The young Charon, possibly undergoing tidal heating from Uranus, may have had a liquid, Carbon Monoxide/Water mixture, ocean below an outer rock hard, sintered, Water ice crust. That freezing out of the Water from the mixture to form the crust, may have concentrated the Carbon Monoxide to the point of separating the two. On its way towards Pluto that crust would have got, colder harder and even more brittle not to mentioned cracked and weakened.

Charon hits Pluto in a glancing blow, brittle ice crust cracks and shatters into huge Water ice chunks, some of which end up strewn across the surface of Pluto as mountains, some escape into orbit. The liquid ocean pours out of the broken shell in a giant flood filling the impact basin with liquid Carbon Monoxide, and liquid Water formed during the heat and pressure of the impact. At the deepest point, the subsequent freezing ice expands to create the central mound. When we see the "toes" at the Northern rim of the ice cream cone, I am expecting to see fjords and canyons carved in the bedrock Water Ice pushed up and ahead of the impact, a landscape similar to that Glacier picture earlier, as Carbon Monoxide/Water ice glaciers, lubricated by Nitrogen and Methane from beneath, carve the landscape.

Evidence for prevailing winds creating the opportunity for aeolian deposition in the lea of cliffs, ridges, hills, mountains and canyons, strongly suspected this and its nice to see some evidence. The comparison to the size of Earth's atmosphere is amazing, Pluto's is bigger than Earth's atmosphere now, it was surely way larger in the past given the modelled loss rate of 500 tonnes a second. The image I most want to see is the one that fits in the corner of the L. That will have that humungous mountain in it.

Finally would it be fair to compare these images and their resolution to an old B&W cathode ray television and the later highest resolution images to a Full HD 1080P TV. It seems about right, in which case this is going to get even more astounding. What a place!

Sherbert, I don't think your fanciful explanation (a grazing impact of Charon created the landscape) takes into the account the TITANIC amounts of energy involved in two planetary bodies of this scale meeting at a speed that exceeds Pluto's escape velocity.

If Charon had a grazing impact with Pluto, a significant part (or almost all) of Pluto's surface would be completely altered by the energy involved, and the ejecta that would rain down on both bodies for an extended time. This would not just leave a nice flat plain and valley. It would not leave a visible scar that would allow you to trace the impact. Not even close.

Such speculation is fun, but there's something to be said for patience in terms of waiting for all the observations to be received as well. We've seen just a tiny amount of the anticipated data thus far, and it's possible--even likely--that more unexpected features are yet to come which will allow formation of much better hypotheses.

--------------------

A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.

Besides, if Charon were to "hit" Pluto at a glancing blow, and wind up intact in a capture orbit, that orbit is already unstable by definition. I would expect Charon and Pluto to merge shortly afterward.

Besides, if Charon were to "hit" Pluto at a glancing blow, and wind up intact in a capture orbit, that orbit is already unstable by definition. I would expect Charon and Pluto to merge shortly afterward.

but since there's not enough data yet there's still room to get fanciful.. so along those lines, if a smaller ex-moon(s) of indeterminate size and composition were to deorbit as it deformed into a diffuse rubble pile that would tend to reduce its monolithic 'impact' legacy as it eventually and more gently joined with Pluto in the post-cratering epoch, depending upon how much of the surface is composed of volatiles that could be liquified by whatever magnitude of energy that may entail, there may be any of all sorts of possible crustal rearrangement resulting in chaotic jumbling of upturned 'mantle' blocks and plains, and all within the 'recent' past, though should such a scenario leave obvious traces on the orbits of the other moons to be ruled out?

Half of the ten KBOs are known to have large satellites! The trend continues among smaller KBOs (allowing for the observational difficulties). Given how common large satellites are around KBOs, I have to think that they formed almost automatically as part of the main KBO formation, as mini-planetary systems. Pluto/Charon would be no exception, in my opinion.

Maybe their isolation in the outer reaches of the Solar System means that their formation was mostly left undisturbed, unlike the chaotic and energetic inner Solar System. So any growing satellites were left in orbit around their primary, without being perturbed away from, or into, them.

I feel like a kid at Christmas time eagerly awaiting the unwrapping of the presents.

Water ice "bedrock: has a density of 0.92, Nitrogen about 1.02 and frozen methane about 0.52. At Pluto's calculated maximum internal pressure, we can say with some confident that water ice would exist as orthorhombic Ice (XI) or possibly some hexagonal ice. There are no major consequences of phase transitions (under normal conditions).

It's not difficult to understand that frozen methane, which behaves like a glass at Plutonian temperatures, would tend to upwell if it ends up below the surface due to impacts, subduction etc.

It's question of how far out of the box you can reasonably think. As Nprev says, there is a vast amount of data yet to come which could change the way we look at Pluto very quickly. So much is tentative.

It's question of how far out of the box you can reasonably think. As Nprev says, there is a vast amount of data yet to come which could change the way we look at Pluto very quickly. So much is tentative.

OK, so how's this for "reasonably far out of the box" ?

1) The Pluto/Charon system orbit is obviously very different from the "regular" planets.

2) The totally unexpected surface morphology of Pluto - almost devoid of craters - is likewise very different from solid bodies (moons) in the outer Solar System.

In other words, Pluto/Charon don't fit.

Ergo, like other "Sednitos", they may be alien worlds captured by the Sun from a passing star:

QUOTE

http://arxiv.org/pdf/1506.03105v1How Sedna and family were captured in a close encounter with a solar siblingLucie Jilkova, Simon Portegies Zwart, Tjibaria Pijloo, Michael Hammer(Submitted on 9 Jun 2015)

Leaving aside how it got there, the Carbon Monoxide ice cap is there on top of Nitrogen, Methane, possibly Neon, sitting on a "bedrock" of Water ice. The Ralph Methane map showed high levels of Methane above the North Pole and the Tombaugh Region and not really anywhere else. From the ideas and figures in other posts the burning question, "is there liquid under the ice cap?"

I'm guessing temperatures in Pluto's Northern Hemisphere on July 14th could be equated to mid July here on Earth. Pluto is about a quarter of the way through it's Northern Summer. So for the Pluto we see in these images, at the moment the temperature is approaching the top of the temperature range near the surface, a time when activity in the atmosphere and on the surface is going to be near its peak. How much of the Methane Ralph shows is on the ground and how much in the lower troposphere? That might have a bearing on localised greenhouse heating. With so many volatile mixtures with triple points around these temperatures, local temperature conditions, microclimates, are going to affect the composition of the surface ices and their physical properties. The team say with more detail they will be able to address these questions. That's going to be a real eyeopener as to whats going on.

With Pluto's axial tilt the highest temperatures are towards the Poles. The Tombaugh region seems to be the quickest route for warmer saturated atmosphere to the North to get to the cold South, but its sort of like a funnel, which would speed up the wind even more. Cold air would try to replace it from the South and meet somewhere in the middle where Charon's gravitational influence is also not to be ignored. Jupiter's Red spot comes to mind. Those polygonal structures are just like windblown ice formations on Earth, however on Pluto, that "hurricane" could last for half a Pluto orbit, over a hundred years. Thats going to leave a significant landmark on the surface.

1) The Pluto/Charon system orbit is obviously very different from the "regular" planets.

2) The totally unexpected surface morphology of Pluto - almost devoid of craters - is likewise very different from solid bodies (moons) in the outer Solar System.

In other words, Pluto/Charon don't fit.

Ergo, like other "Sednitos", they may be alien worlds captured by the Sun from a passing star:

While Pluto's orbit is unlike that of the "regular" planets, it is very typical of the "plutinos", which are, like Pluto, in a 3:2 resonance with Neptune. There are a great many such objects, of which Pluto is merely the largest.

They were originally in closer orbits to the Sun, but would have been swept up by Neptune as it moved outward and trapped in the 3:2 resonance.

Sedna's unusual orbit makes an extrasolar origin possible, but Pluto's orbit looks quite typical of the numerous objects that formed in the inner Kuiper Belt.

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